The present invention pertains to foam pads for buffing and, more particularly, to rotary pads made from foam string material for buffing and polishing painted or similarly finished surfaces.
Foam buffing pads are now used in many buffing and polishing operations where synthetic or natural fiber pads, such as tufted wool pads, had previously been used. In particular, open cell polyurethane foam pads, with both reticulated and nonreticulated cell structures, have become particularly popular. However, despite certain advantages of polymer foam pads over fibrous and tufted pads, there are still a number of inherent disadvantages attendant the use of foam pads. These disadvantages include "chatter" or jumping of the pad by excess frictional surface contact between flat working surface portions of the pad and the surface of the work being finished; splattering of the polish or other finishing compound as a result of the compound being thrown radially outwardly by centrifugal force; and, burning of the surface of the work being finished by the high speed outer edge portions of the rotary pad.
Attempts have been made to minimize or eliminate these problems by varying the type and density of foam used and by changing the working surface of the pads. Initially, foam pads were made of a generally cylindrical disc with a flat planar working face and, typically, with a radiused outer edge providing the transition between the working face and the outer cylindrical edge face. However, flat pads are particularly subject to chatter and provide little deterrent to the splatter of polish. Flat faced pads also give the operator little control over variations in the working surface actually in contact with the work surface being finished or polished. One attempt at solving the problems presented by flat foam buffing pads was the introduction of buffing pads having working surfaces with a convoluted or waffle shape. One such pad was previously made by Lake Country Manufacturing, Inc. Although this pad provided variable working surface contact by varying operator-applied pressure, surface contact was somewhat difficult to control and the pad did little to prevent splatter. A different approach to solving the prior art problems is shown in U.S. Pat. No. 5,527,215 where a cylindrical foam pad has a recessed center portion or portions within which the polishing compound may be trapped against radial splatter. This pad also provides the ability to alter the working surface contact by varying operator-applied pressure. However, neither of the foregoing pads adequately solves all of the prior art problems.
One recent attempt to solve the remaining problems inherent in foam buffing pads has resulted in the introduction of a pad having a working face comprising a concave central contact surface which increases radially inwardly with increasing pad compression by the operator. This pad has helped reduce chatter and improved operator control of the working surface contact area.
However, all of the foregoing foam pads are characterized by their monolithic body construction in which the foam bodies are made of a single uniform layer of foam material and, as a result, have an uninterrupted working face regardless of variations in face contour. As a result, monolithic polymeric foam pads remain subject to pad chatter, relatively rapid working surface contamination, undesirable swirl marks, and susceptibility to tearing out of large pieces of the foam body as a result of contact with obstructions during the finishing operation.
As a result, foam buffing and finishing pads have never completely replaced pads made with tufted wool fibers or other natural or synthetic fibers. U.S. Pat. No. b 2,690,661 shows an attempt to provide a hybrid pad comprising a tufted construction of cotton strands to which an outer layer of cellulose material is intimately bonded. If a pad of this construction was ever commercialized, its use today is not known.